The present invention relates to a germ-free filling/packaging system adapted to sterilize containers and then to fill these containers with germ-free food or drink, i.e. a method and apparatus. Between each pair of successive processes or within each process, the method and apparatus convey containers and simultaneously achieve adequate sterilization thereof, while maintaining a sealed condition within each process or betwen processes.
It is well known from Japanese Patent publication Nos. 1980-3218 1980-4618 to perform sterilization, filling and sealing of the containers within a germ-free chamber while conveying these containers. According to said Patent Publication No. 1980-3278, the germ-free chamber is maintained at a pressure slightly higher than that of the outer air and thereby the outer air is prevented from entering thereinto.
However, it is difficult to constantly maintain the inner pressure of the germ-free chamber at such a high level and, once the inner pressure has dropped, it is impossible to convey a succeeding container into the germ-free chamber. Thus this system of prior art is disadvantageous in that continuous processes can not be carried out.
Said Patent Publication No. 1980-4618 discloses a system adapted to establish a sealing relationship between the germ-free chamber and the outer air by utilizing liquid. However, there is no provision to convey the containers into and within the germ-free chamber, or to convey the containers out of the germ-free chamber after being filled with food or drink, or to maintain the condition of the germ-free chamber.
The inventor of the present application has disclosed a countermeasure to solve these problems in Japanese Disclosure Gazette No. 1986-203322.
This solution is to provide rotatable partitions adapted for sealing the respective processes from the outer air and the containers are conveyed by recesses formed in these rotatable partitions for this purpose. Accordingly, such solution is certainly advantageous in that the respective processes are always isolated from the outer air and the outer air is prevented from directly flowing into the respective processes. However, this system of prior art utilizing the rotatable partitions has been found to be inadequate in the sealing effect against the outer air. Specifically, germicide in the sterilizing process is apt to leak out and into the outer air and thereby injure an operator's health. Also, germs in the outer air sometimes enter into the respective process, destroying the germ-free condition maintained therein.
Additionally, according to the inventor's Japanese Disclosure Gazette No. 1986-203322, H.sub.2 O.sub.2 mist which has been used in the sterilizing chamber for sterilization is then dried in a drying chamber by hot air. However, H.sub.2 O.sub.2 mist is apt to cling to the conveyor means in the sterilizing chamber and, therefore, an operation for removing this is required. Further-more, sometimes H.sub.2 O.sub.2 mist is condensed and accumulated on the conveyor means. In such case, droplets of germicide cling to the containers also and an operation for removing said droplets is required.
Also in the drying chamber, the individual containers come into contact with the same locations of this chamber, so germicide is apt to be condensed on these locations. As a consequence, the drying chamber can not provide the expected function, sometimes leaving a certain quantity of germicide still not dried.
Moreover, when conveyor arms are used as the conveyor means in the drying chamber, these conveyor arms intercept hot air streams and thereby obstruct effective drying.